Topping L30 Review and Measurements

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by Marvey, Jun 28, 2021.

  1. mocenigo

    mocenigo Acquaintance

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    Well, they use ASR as their mouthpiece, and some shops like Apos have informed the customers. It is clear that Topping has a very flawed comminication.

    Ok, my experience is mostly with my previous favourite, the Lehmann Black Cube Linear.


    Very well, anyway I am not judging by looking only at SINAD, of course, and if you read my posts "there" you'll see that I have been having discussion with some objectivism jihadis.
     
  2. mocenigo

    mocenigo Acquaintance

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    Some retailers just relied on the customers to promise to destroy the old units. Probably because Topping told them to do so and did not want to pay shipping back. It is, honestly, reckless to say the least.
     
  3. Roget

    Roget Acquaintance

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    Can you explain the bottom second and third boxes? They are blue instead of purple.
     
  4. Marvey

    Marvey Super Friend

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    Now this is kind of super duper funky. The R channel seems totally off. Is Topping suffering from Soncoz syndrome? Did I get a bum unit? Note that we didn't catch this before because the levels in the Triple Sine Dashboard were too low, at the cusp of the deviation between L and R channels.

    Topping L30
    THD+N vs power
    32 ohm load, 1kHz, 90kHz bandwidth
    upload_2021-6-29_17-26-23.png

    Let's confirm via FFT. Push this up to 2Vrms.

    Topping L30
    1kHz 2Vrms 32 ohm load
    upload_2021-6-29_17-3-46.png

    Yep confirmed. At higher voltages, the R channel (red) is completely out of whack with the left channel (blue). This is troubling. I DO NOT RECOMMEND! LOLZ!

    [​IMG]

    To be honest, I really wish I hadn't seen this. These are the kind of things that make people think that gear made in China is cheap or that China cannot make good stuff - which is not true at all. It should be noted that since the Changstar days, everyone knows I've been a magnet for "defective" gear. Or maybe I'm the anti-Amir where stuff he shills happens to have measurement anomalies. Funny how this happens. This is two out of two now with respect to peer-review of ASR measurements of gear the topping of the heap.
     

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    Last edited: Jun 29, 2021
  5. Marvey

    Marvey Super Friend

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    Well, it turns out that the behavior only happens with the 32-ohm load. The 300-ohm load is perfect. This makes total sense now with respect to the Triple Sine Dash because it doesn't get anywhere near 2Vrms for the 32-ohm headphones. The R channel seems current started for lower impedance loads which ask for the electrons.

    Topping L30
    THD+N vs power
    300 ohm load, 1kHz, 90kHz bandwidth
    upload_2021-6-29_17-19-25.png
     
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  6. Marvey

    Marvey Super Friend

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    I'm done here. This was a waste of my time. I'd be happy if anyone has another L30 to send to me so I can chalk this off as a defective unit. (Actually I got one more measurement, the potentiometer tracking...)
     
  7. Biodegraded

    Biodegraded Friend

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    Also please listen through some 32 Ohm headphones at 2V and tell us about the distortion you hear in R ;)
     
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  8. Brause

    Brause Friend

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    Yep, it sounds flat and boring. When I reported this elsewhere I was told I had listened wrong - and that I was unprofessional :).
     
  9. atomicbob

    atomicbob dScope Yoda

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    How do you know this isn't representative of behavior for the rank & file purchases as opposed to cherry picked for review? (rhetorical question)
     
  10. mocenigo

    mocenigo Acquaintance

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    Oh, thank you @dncnexus for calling my reply a shitpost...
     
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  11. Marvey

    Marvey Super Friend

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    If that's you in the photo, it could be because we are old school have heard things from the past (actually not so recent past) that sounded better than these new trendy "state of the art" designs. It's becoming obvious where the disconnect lies. It's generational - having exposure to certain kinds of gear - and cost cutting, simplification. Also, no one knows how to design discrete anymore.

    I didn't see it as calling it out. The point is that confirmation bias works both ways. For certain I am guilty of this - and this is why I really like doing blind tests, mostly informal because of speed and ease, and at times formal double-blind level matched to a mV.

    To more seriously answer your question: it's not just the global negative feedback. It's actually the TPA6120 output device in a Nested Composite Feedback loop. We've seen this part used in quite a few other amp designs and they all do sound very similarly to my ears. Contrary to how well a single steady sine wave (or two sine waves) may measure, different parts will sound different.

    For example, for fun I replaced the Modi 3+'s output amp OPA1688 with an OPA1656 because I wanted to change the sound from one that "fat" (fun and happy was an intentional voicing) to one which was more neutral (serious). Regardless, the Modi+ still measures with 110db SINAD at 0fbFS and from a cursory look, the same distortion pattern.
     
    Last edited: Jun 30, 2021
  12. Marvey

    Marvey Super Friend

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    I have a bone to pick with how ASR does this. The 2V into an HD650 won't be fatal, at least for a short duration. A longer duration could cause the voice coils to heat up and melt. The issue which I have is that transducers pushed to this level will distort massively. Magnitudes. Not one order or two orders. More like six to nine orders of magnitudes higher distortion. That is up to x1000000000. This is going to mask any distortion from the DAC or amp. Despite the defect, at 2Vrms, we would still be under 0.005 THD+N. That's darn low.

    ASR is hearing the headphone distort. Not the amp. ASR uses tales of "I cranked it up and heard distortion" as anecdotes to support his narrative. He has also shown no ability to hear the massive THD+N of the plate amps of the JBL LSR305 powered monitors in his very positive review of it.

    We do not. Statistics tell us that we should sample more. 30 units for a 90% confidence level? However much I think that Topping rep John Yang at ASR is dickhead because he loves to shit on competitors products and would utterly love to take the low road like Amir, I will not. We need to give Topping the benefit of the doubt. Of course seeing what's happened with the Soncoz DAC's measurement irregularities, this becomes a bit more difficult.

    We can laugh, we can shake our heads, we but still need to be fair.
     
    Last edited: Jun 30, 2021
  13. Biodegraded

    Biodegraded Friend

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    There are so many examples of this, in which he purports to listen at >>100 dB and says he hears the amp distorting - and nobody at ASR ever suggests it might be the headphones. Evidently these people have never looked at headphone measurements before (or even listened to many).
     
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  14. dncnexus

    dncnexus Friend

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    No need to get butthurt over a dislike. It's not that serious. And I was utilizing it as a dislike rather than a shitpost, I think being passive aggressive like that deserves a dislike imo, others might not have used the dislike/shitpost, but it's obvious they didn't agree based on the replies you got after that comment.

    Anyways it's a dislike on the internet, get over it.
     
  15. dsavitsk

    dsavitsk Friend

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    Apologies if this has been addressed elsewhere. Is there a reason not to toggle between actual headphones instead of resistors?
     
  16. Marvey

    Marvey Super Friend

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    No reason at all, especially at these new set of realistic voltage levels per @atomicbob's suggestion: 0dBu, -10dBu, -20dBu. Lemme get back and redo the TripleX Sin Panel with the HD650 and Grado SR225X as the loads. Now at 2Vrms (+8.23dBu) I would hesitate. The drivers of the Focal headphones will slam well before 2Vrms. The Grados would probably catch on fire given their sensitivity.

    The board has a nice provision to use real headphones as loads already.
    breakout.jpg

    The panel in the first post is still experimental. Maybe I should use real loads? Sorry, I'm such a geek addicted to fun and learning that I can't turn this suggestion down. :rolleyes:
     
    Last edited: Jun 30, 2021
  17. Biodegraded

    Biodegraded Friend

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    If you do you should show the impedance curve for any significantly variable ones (eg Senns, Focals) so people can appreciate how the load varies.

    Maybe the 4 rows you have now, and a couple more rows with actual headphones: one with a Senn or Focal, and one with an efficient planar or a dynamic of low and not-too-variable impedance (Grado?), with a small impedance-vs-frequency profile on the left of each new row instead of the text description. That could be a good combo to show the variation in THD results vs frequency with nominal loads vs real loads of representative character.
     
  18. Marvey

    Marvey Super Friend

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    Just get rid of the current rows and use the four headphones that you suggested. Add a CFA IEM or HE6se row when the amp is suited for it.

    Nothing beats using more realistic tests with measurements.
     
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  19. Elnrik

    Elnrik Super Friendly

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    I think it would be interesting to see both. A 32 and 300 synthetic load and a 32 and 300 ohm headphone load. I assume you'll see differences especially as freq and impedance changes.
     
    Last edited: Jun 30, 2021
  20. dsavitsk

    dsavitsk Friend

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    I'm primarily curious about the effects of back EMF, especially where it is fed through a feedback network.
     

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